The investigation of the inclusion complexes obtained with heptakis-(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-Cdx) or heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin (PM-beta-Cdx) and either 1-anilinonaphthalene-8-sulfonate (ANS) or 2-p-toluidinylnaphthalene-6-sulfonate (TNS) was carried out by means of ionspray mass spectrometry, both in the positive and in the negative ion mode. All the data collected showed that the heptakis-(2,3, 6-tri-O-methyl)-beta-cyclodextrin interacted to a very little extent with TNS and not at all with ANS. On the contrary, heptakis-(2,6-di-O-methyl)-beta-cyclodextrin formed complexes with both aromatic molecules showing a more effective interaction with TNS. Small variations in the number of methoxy substituents in the DM-beta-Cdx molecule did not affect the complexation behaviour significantly. The spectra recorded at different orifice potentials indicated that the complex of heptakis-(2,6-di-O-methyl)-beta-cyclodextrin with TNS is more stable than the one formed with ANS. These results agreed on one hand with the conformations of both the heptakis-(2,6-di-O-methyl)-beta-cyclodextrin and heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin, established by X-ray diffraction studies, and, on the other hand, with the different complexation behaviour of the guest aromatic molecules due to their own geometry. (C) 1997 Elsevier Science Ltd.
Effect of methylation of beta-cyclodextrin on the formation of inclusion complexes with aromatic compounds. An ionspray mass spectrometry investigation
GAROZZO, DOMENICO;
1997-01-01
Abstract
The investigation of the inclusion complexes obtained with heptakis-(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-Cdx) or heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin (PM-beta-Cdx) and either 1-anilinonaphthalene-8-sulfonate (ANS) or 2-p-toluidinylnaphthalene-6-sulfonate (TNS) was carried out by means of ionspray mass spectrometry, both in the positive and in the negative ion mode. All the data collected showed that the heptakis-(2,3, 6-tri-O-methyl)-beta-cyclodextrin interacted to a very little extent with TNS and not at all with ANS. On the contrary, heptakis-(2,6-di-O-methyl)-beta-cyclodextrin formed complexes with both aromatic molecules showing a more effective interaction with TNS. Small variations in the number of methoxy substituents in the DM-beta-Cdx molecule did not affect the complexation behaviour significantly. The spectra recorded at different orifice potentials indicated that the complex of heptakis-(2,6-di-O-methyl)-beta-cyclodextrin with TNS is more stable than the one formed with ANS. These results agreed on one hand with the conformations of both the heptakis-(2,6-di-O-methyl)-beta-cyclodextrin and heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin, established by X-ray diffraction studies, and, on the other hand, with the different complexation behaviour of the guest aromatic molecules due to their own geometry. (C) 1997 Elsevier Science Ltd.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
